I have been trying to decide the best way to add a third brake light to my 85 XJS. I found a trunk mounted brake light from a convertible on e-bay.
Is there an auxiliary wiring harness (usually used for trailers)?
Should I modify a trailer wiring Kit?
I have been told or have read that it is not a good idea to tap into the brake light wiring due to the bulb failure relay may fail or become damaged.
Any ideas? Thanks

 

Hello,

Honestly, you'd be better off just going to a bright LED bulb in your taillights / brake.

If you really want to be seen, you could put a blinking variant in, which is effective and very annoying ;-).

Cheers,

Jeff

 

I like this one:

BackOFF? XP Brake Light Module - Signal Dynamics

mode 2 is almost legal. the law allows 4 flashes not 5. but who's counting?

following drivers inevitably go around or leave more space. either one is fine
by me

 

NO...DONT DO IT. Why ruin not only the trunk lid but the looks of the car.
I take it its a coup. Get one that goes behind the rear window.

 

I have recently added one. I used a very svelte light made by Hella, bought here:

Surface Mount Slimline LED Third Brake Light Red Lens - Car Builder Solutions - Kit Car Parts and Accessories

It is illuminated by LEDs, and is only about 1/4 inch thick and sticks on just below the boot lock channel above the number plate. I ran a wire from the LHS brake light cluster along the boot lid and through a small hole I drilled behind the LED. The whole thing is waterproofed by the 3M-type peelable adhesive the light is backed with. As it is LED and so practically no current draw, the brake light failure warning system does not even see it, so no worries there.


A really good safety mod IMO, and much nicer than the guastly OEM boottop module.

Greg

 

Aha! All is revealed.

You have a hoist ... how very unsportsmanlike

I personally would prefer a inside third brakelight mounted
at the roofline like some later cars. The higher the better.

 

I paid my dues Plums! 40 years man and Boy, on my back with crap falling into my eyes! Bought it as a retirement present to myself, MUCH better value than a cruise, and amazingly not that expensive. And it is quite wonderful!

Greg

 

I'm sure it is. I used to have the run of an eight bay dealership
garage. Alignment machine, brake lathe, and every special tool
known to man. Several decades ago.

Used commercial units are available around here any day
of the week, any week. Cheap!

The problem is not having space to install it.

... some day ...

 

That looks great Greg! Thanks

 

-I see you and your car are famous, George ....lol

 

Instead or adding the third taillight to the trunk why not add red LEDs to you reverse lights. They would act light a third taillight without ruining your trunk lid. I was planning on doing that to my 89 to remove third taillight.

 

Not a bad idea, can you get sufficiently bright festoon LED bulbs to fit?
Greg

 

Your original answer was better.

It is too much to expect following drivers to actually think.

Your reverse lights are above the add on, but if using for third brakelight,
they had better be RED and BRIGHT.

White festoons can be had on ebay very cheap and very bright if you buy
the right ones. It's a matter of led count and orientation. Red, I don't know.

 

on my *$, since I bought an extra back glass for a spare, it had the mount area for an inside mount, found one on ebay and tapped into the brake lights with not problem. Of course at the time I did this, I was replacing the rubber seals on the front and back glass